Vacuum-responsive choke control



Nov. 23, 1954 H. M. CAMPBELL 2,695,033

VACUUM-RESPONSIVE CHOKE CONTROL Filed Aug. 2. 1951 Fig.

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United States Patent 2,695,033 Patented Nov. 23, 1954 fine 2,695,033 VACUUM-RESPONSIVE CHOKE CUNTROL Herbert M. Campbell, Paris, Tex. Application August 2, 1951, Serial No. 239,965 2 Claims. (Cl. 137-481) This invention relates to new and useful improvements and structural refinements in choke controls for internal combustion engines such as those of automobiles, or the like, and the principal object of the invention is to provide an automatic choke control which is responsive to variations in vacuum in the intake manifold of the engine, so that when the engine is stationary, the choke is closed, but is automatically opened when the engine is running.

ln particular, the instant invention is intended as an accessory or attachment for engines equipped with a manual choke control, an important feature of the invention residing in the provision of means for readily installing the saine on engine carburetors of conventional types.

With the above more important objects and features in view, and such other objects and features as may become apparent as this specification proceeds, the invention consists essentially of the arrangement and construction of par'tsl as illustrated in the accompanying drawings, in wi ic i:

Figure l is a side elevational view of an engine, showing the invention associated with the carburetor;

Figure 2 is a longitudinal sectional view of the invention per se; and

Figure 3 is a transverse sectional detail, taken substantially in the plane of the line 3--3 in Figure 2.

isike characters of reference are employed to designate like parts in the specification and throughout the several views.

Referring now to the accompanying drawings in detail, the general reference character 1t) designates an internal combustion engine having a carburetor 12 and an intake manifold 14, the air intake of the carburetor 12 being illustrated at 16 and containing the usual butterfly choke valve 18 which is carried by a transverse shaft 2i) having a control lever 22 at one end thereof, as will be clearly apparent.

The control lever 22 carries the usual swivel block 24 whereby the control lever is ordinarily connected to a Bowden cable 26 having a manual control button 25S on the instrument panel 30 of the vehicle, but when the invention is used, the swivel block 24, rather than being connected to the cable 26, has secured therein a short length of wire 32 having a helical portion 34 at one end thereof.

The invention also contemplates the provision of an actuating cylinder 36 which has an end wall 38 at one end and an aperture disc 40 which is secured in the remaining end of the cylinder by a screw 42.

A plunger 44, mounted upon a reciprocable rod 46, is siidable in the cylinder 36, the plunger 44 consisting of a leather cup disposed between a pair of washers 4S which are clamped against the leather cup by a pair of nuts dil, and it wifi be noted that a compression spring 52 is positioned in the cylinder 36 between the plunger 44 and the end wall 38, so as to urge the plunger outwardly in the direction of the arrow 54.

Means are provided for a cushioning stop to the outward movement of the plunger, these means consisting of a washer 56 adjustably sustained in position on the rod 46 by a nut 53, while a compression spring 60 is positioned between the washer 56 and a second washer 62 placed on the rod 46 against the inner surface of the disc 4l). Of course, the rod 46 projects outwardly through the apertured disc 40, and since the spring 52 is much stronger than the spring 60, the spring 52 will slide the plunger 44 iii) and the rod 46 in the `direction of the `arrow 54 until the spring 16 is fully compressed. The aforementioned coiled portion 34 of the wire 32 is attached to the outer end of the rod 46 'by a pair o'f nuts '66 and the device is so adjusted that when the rod 44 is slid fully outwardly by the spring 52, the lever 22 of the choke valve 18 is in its closed position, as shown in Figure l.

The cylinder 36 is suitably supported by a pair of U- shaped hangers 6d which are attached by suitable screws to the end portion of a wire supporting member 72, the latter being suitably attached as at 74 to the engine. The end wall 38 of the cylinder 36 has secured therein one arm 76 of a T-coupling 73, the second arm of which is connected to a windshield wiper hose 80, while the third arm of the coupling communicates through the medium of a tube 82 with the intake manifold 14.

l/Vhen the engine 10 is stationary, the spring S2 will sustain the rod 46 in its outwardly slid position wherein the choke valve 18 is closed, but when the engine is running, sub-atmospheric pressure in the manifold 14 will create a vacuum in the right hand portion of the cylinder 36, thus causing the plunger 44 to be slid inwardly and opening the choke valve in the direction of the arrow 86 in Figure l.

ln instances where it is necessary to start the engine in extremely cold weather, it may be preferred to hold the choke in its closed position for a brief period of time after the engine is running, and this may be achieved by providing a wire extension S8 with a pair of eyes 90, 92, the eye 9i? being positioned on the aforementioned cable 26 in front of a stop collar 94, while the eye 92 is positioned on the wire 32 as shown in Figure 1. With the engine stationary and the choke lever 22 in its closed position as shown, the button 21? may be pulled outwardly so that the eye 92 is disposed immediately adjacent the swivel block 24, and as long as the button 28 remains pulled downwardly, the eye 92 will prevent the choke lever 22 from being opened by the plunger 44 even though the engine has started running.

lt is believed that the advantages and use of the invention will be clearly understood from the foregoing disclosure and accordingly, further description thereof at this point is deemed unnecessary.

While in the foregoing there has been shown and described the preferred embodiment of this invention, it is to be understood that minor changes in the details of construction, combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as claimed.

Having described my invention, what is claimed to be new is:

l. A vacuum-responsive choke control, comprising an actuating cylinder having front and rear ends, a plunger reciprocable in said cylinder, a vacuum tube connected to the rear end of the cylinder, a spring between said rear end and said plunger for urging the latter forwardly, a stem provided on the plunger and extending outwardly through the front end of the cylinder for connection to a choke valve, and adjustable stop means provided on said stern for limiting forward movement thereof, said stop means including a resilient spring surrounding said stem and reacting against a portion of said stern and said forward end of said cylinder in opposition to said first mentioned spring,

2. A vacuum-responsive choke control, comprising an actuating cylinder having front and rear ends, a plunger recipiocable in said cylinder, a vacuum tube connected to the rear end of the cylinder, a spring between said rear end and said plunger for urging the latter forwardly, a stem provided on the plunger and extending outwardly through the front end of the cylinder for connection to a choke valve, and adjustable means provided on said stem for limiting forward movement thereof and bracket means for attaching said cylinder to a carburetor, said bracket means including a substantially V-shaped wire rod adapted at the base thereof for attachment to a carburetor, a pair of spaced eyes provided at the upper ends o f said rod, a pair of U-shaped clamps embracing longitudinally spaced portions of said cylinder, and a pair of screws extending E through the respective clamps and eyes for securing the Number clamps to said rod. 1,811,354 1,881,560 References Cited in the file of this patent 2,017,890 5 2,398,17 8

UNITED STATES PATENTS Number Name Date Joeck June 23, 1931 Heitger Oct. 11, 1932 Bracke Oct. 22, 1935 Ellison Apr. 9, 1946 

